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bdcffc5a GKH |
1 | config VT |
2 | bool "Virtual terminal" if EXPERT | |
3 | depends on !S390 | |
4 | select INPUT | |
5 | default y | |
6 | ---help--- | |
7 | If you say Y here, you will get support for terminal devices with | |
8 | display and keyboard devices. These are called "virtual" because you | |
9 | can run several virtual terminals (also called virtual consoles) on | |
10 | one physical terminal. This is rather useful, for example one | |
11 | virtual terminal can collect system messages and warnings, another | |
12 | one can be used for a text-mode user session, and a third could run | |
13 | an X session, all in parallel. Switching between virtual terminals | |
14 | is done with certain key combinations, usually Alt-<function key>. | |
15 | ||
16 | The setterm command ("man setterm") can be used to change the | |
17 | properties (such as colors or beeping) of a virtual terminal. The | |
18 | man page console_codes(4) ("man console_codes") contains the special | |
19 | character sequences that can be used to change those properties | |
20 | directly. The fonts used on virtual terminals can be changed with | |
21 | the setfont ("man setfont") command and the key bindings are defined | |
22 | with the loadkeys ("man loadkeys") command. | |
23 | ||
24 | You need at least one virtual terminal device in order to make use | |
25 | of your keyboard and monitor. Therefore, only people configuring an | |
26 | embedded system would want to say N here in order to save some | |
27 | memory; the only way to log into such a system is then via a serial | |
28 | or network connection. | |
29 | ||
30 | If unsure, say Y, or else you won't be able to do much with your new | |
31 | shiny Linux system :-) | |
32 | ||
33 | config CONSOLE_TRANSLATIONS | |
34 | depends on VT | |
35 | default y | |
36 | bool "Enable character translations in console" if EXPERT | |
37 | ---help--- | |
38 | This enables support for font mapping and Unicode translation | |
39 | on virtual consoles. | |
40 | ||
41 | config VT_CONSOLE | |
42 | bool "Support for console on virtual terminal" if EXPERT | |
43 | depends on VT | |
44 | default y | |
45 | ---help--- | |
46 | The system console is the device which receives all kernel messages | |
47 | and warnings and which allows logins in single user mode. If you | |
48 | answer Y here, a virtual terminal (the device used to interact with | |
49 | a physical terminal) can be used as system console. This is the most | |
50 | common mode of operations, so you should say Y here unless you want | |
51 | the kernel messages be output only to a serial port (in which case | |
52 | you should say Y to "Console on serial port", below). | |
53 | ||
54 | If you do say Y here, by default the currently visible virtual | |
55 | terminal (/dev/tty0) will be used as system console. You can change | |
56 | that with a kernel command line option such as "console=tty3" which | |
57 | would use the third virtual terminal as system console. (Try "man | |
58 | bootparam" or see the documentation of your boot loader (lilo or | |
59 | loadlin) about how to pass options to the kernel at boot time.) | |
60 | ||
61 | If unsure, say Y. | |
62 | ||
63 | config HW_CONSOLE | |
64 | bool | |
65 | depends on VT && !S390 && !UML | |
66 | default y | |
67 | ||
68 | config VT_HW_CONSOLE_BINDING | |
69 | bool "Support for binding and unbinding console drivers" | |
70 | depends on HW_CONSOLE | |
71 | default n | |
72 | ---help--- | |
73 | The virtual terminal is the device that interacts with the physical | |
74 | terminal through console drivers. On these systems, at least one | |
75 | console driver is loaded. In other configurations, additional console | |
76 | drivers may be enabled, such as the framebuffer console. If more than | |
77 | 1 console driver is enabled, setting this to 'y' will allow you to | |
78 | select the console driver that will serve as the backend for the | |
79 | virtual terminals. | |
80 | ||
81 | See <file:Documentation/console/console.txt> for more | |
82 | information. For framebuffer console users, please refer to | |
83 | <file:Documentation/fb/fbcon.txt>. | |
84 | ||
85 | config UNIX98_PTYS | |
86 | bool "Unix98 PTY support" if EXPERT | |
87 | default y | |
88 | ---help--- | |
89 | A pseudo terminal (PTY) is a software device consisting of two | |
90 | halves: a master and a slave. The slave device behaves identical to | |
91 | a physical terminal; the master device is used by a process to | |
92 | read data from and write data to the slave, thereby emulating a | |
93 | terminal. Typical programs for the master side are telnet servers | |
94 | and xterms. | |
95 | ||
96 | Linux has traditionally used the BSD-like names /dev/ptyxx for | |
97 | masters and /dev/ttyxx for slaves of pseudo terminals. This scheme | |
98 | has a number of problems. The GNU C library glibc 2.1 and later, | |
99 | however, supports the Unix98 naming standard: in order to acquire a | |
100 | pseudo terminal, a process opens /dev/ptmx; the number of the pseudo | |
101 | terminal is then made available to the process and the pseudo | |
102 | terminal slave can be accessed as /dev/pts/<number>. What was | |
103 | traditionally /dev/ttyp2 will then be /dev/pts/2, for example. | |
104 | ||
105 | All modern Linux systems use the Unix98 ptys. Say Y unless | |
106 | you're on an embedded system and want to conserve memory. | |
107 | ||
108 | config DEVPTS_MULTIPLE_INSTANCES | |
109 | bool "Support multiple instances of devpts" | |
110 | depends on UNIX98_PTYS | |
111 | default n | |
112 | ---help--- | |
113 | Enable support for multiple instances of devpts filesystem. | |
114 | If you want to have isolated PTY namespaces (eg: in containers), | |
115 | say Y here. Otherwise, say N. If enabled, each mount of devpts | |
116 | filesystem with the '-o newinstance' option will create an | |
117 | independent PTY namespace. | |
118 | ||
119 | config LEGACY_PTYS | |
120 | bool "Legacy (BSD) PTY support" | |
121 | default y | |
122 | ---help--- | |
123 | A pseudo terminal (PTY) is a software device consisting of two | |
124 | halves: a master and a slave. The slave device behaves identical to | |
125 | a physical terminal; the master device is used by a process to | |
126 | read data from and write data to the slave, thereby emulating a | |
127 | terminal. Typical programs for the master side are telnet servers | |
128 | and xterms. | |
129 | ||
130 | Linux has traditionally used the BSD-like names /dev/ptyxx | |
131 | for masters and /dev/ttyxx for slaves of pseudo | |
132 | terminals. This scheme has a number of problems, including | |
133 | security. This option enables these legacy devices; on most | |
134 | systems, it is safe to say N. | |
135 | ||
136 | ||
137 | config LEGACY_PTY_COUNT | |
138 | int "Maximum number of legacy PTY in use" | |
139 | depends on LEGACY_PTYS | |
140 | range 0 256 | |
141 | default "256" | |
142 | ---help--- | |
143 | The maximum number of legacy PTYs that can be used at any one time. | |
144 | The default is 256, and should be more than enough. Embedded | |
145 | systems may want to reduce this to save memory. | |
146 | ||
147 | When not in use, each legacy PTY occupies 12 bytes on 32-bit | |
148 | architectures and 24 bytes on 64-bit architectures. | |
149 | ||
150 |